A term defined in the Renaissance that simply means doing something extremely well without showing effort. A main synonym would be "grace". It also can apply to not trying too hard to acheive something (i.e. women putting on makeup). It was popularize in Castiglione's Book of the Courtier, stating that it was a necessary trait for a perfect Courtier.
The magician showed much sprezzatura as he performed his act with ease. It is as though it comes to him naturally